The organisation running the event is now Mountbatten and information - including registering interest - can be found at https://www.mountbatten.org.uk/randonnee2026
You can stay at the cycle-friendly Premier Inn at Newport which means a 25 minute cycle to Wootton or East Cowes for one of the starts; subhect to confirmation here are 5 starting points, East Cowes, Wootton, Bembridge, Ventnor and Freshwater/Yarmouth.
A PDF of the previous route can be found at:
https://www.cycleisland.co.uk/images/map_1.pdf though check latest information from Mountbatten and, critically, what direction is being taken.
There are options for getting to the Isle of Wight:
Take the train to Southampton then the Red Funnel ferry to East Cowes; these run every hour and the crossing takes an hour.
Take the train to Portsmouth Harbour then the ferry to Fishbourne; these run every 40 minutes and the crossing takes 45 minutes. Portsmouth Harbour to Ryde is also possible.